Contaminant Candidate List 3 (CCL 3)

CCL 3 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or anticipated to occur in public water systems, and which may require regulation under the Safe Drinking Water Act (SDWA). The list includes, among others, pesticides, disinfection byproducts, chemicals used in commerce, waterborne pathogens, pharmaceuticals, and biological toxins. The Agency considered the best available data and information on health effects and occurrence to evaluate thousands of unregulated contaminants. EPA used a multi-step process to select 116 candidates for the final CCL 3. The final CCL 3 includes 104 chemicals or chemical groups and 12 microbiological contaminants.

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Overview of CCL 3 Process

In developing the CCL 3, EPA implemented an improved process from that which was used for CCL 1 and CCL 2. This new process builds on evaluations used for previous CCLs and was based on substantial expert input and recommendations from the National Academy of Science's National Research Council (NRC) and the National Drinking Water Advisory Council (NDWAC).

EPA used a multi-step CCL process to identify contaminants for inclusion on the final CCL 3. The key steps include:

Applying screening criteria to the universe EPA identified almost 600 of those contaminants that should be further evaluated (the preliminary CCL or PCCL) based on a contaminant's potential to occur in public water systems and the potential for public health concern.

EPA then selected 116 contaminants from the PCCL to include on the CCL based on more detailed evaluation of occurrence and health effects and expert judgment.

EPA incorporated information from the public, expert input, and expert review in the CCL process.

CCL 3 Process Flow Diagram & Technical Support Documents

The CCL 3 Process Flow Diagram provides a visual overview of the CCL 3 and links to the support documents pertaining to each step in the process. Click the diagram to view/download the support documents for CCL 3.

For additional CCL 3 support documents and more detailed information on the contaminants, visit docket number EPA-HQ-OW-2007-1189 at Regulations.gov.

CCL 3 List

Chemical Contaminants

It is an industrial chemical used in the production of other substances.

1,1-Dichloroethane

75-34-3

It is an industrial chemical used as a solvent.

1,2,3-Trichloropropane

96-18-4

It is an industrial chemical used in paint manufacture.

1,3-Butadiene

106-99-0

It is an industrial chemical used in rubber production.

1,3-Dinitrobenzene

99-65-0

It is an industrial chemical and is used in the production of other substances.

1,4-Dioxane

123-91-1

It is used as a solvent or solvent stabilizer in the manufacture and processing of paper, cotton, textile products, automotive coolant, cosmetics and shampoos.

17alpha-estradiol

57-91-0

It is an estrogenic hormone and is used in pharmaceuticals.

1-Butanol

71-36-3

It is used in the production of other substances, and as a paint solvent and food additive.

2-Methoxyethanol

109-86-4

It is used in consumer products, such as synthetic cosmetics, perfumes, fragrances, hair preparations, and skin lotions.

2-Propen-1-ol

107-18-6

It is used in the production of other substances, and in the manufacture of flavorings and perfumes.

3-Hydroxycarbofuran

16655-82-6

It is a carbamate, and is a pesticide degradate. The parent, carbofuran, is used as an insecticide.

4,4'-Methylenedianiline

101-77-9

It is used in the production of other substances, and as a corrosion inhibitor and curing agent for polyurethanes.

Acephate

30560-19-1

It is used as an insecticide.

Acetaldehyde

75-07-0

It is used in the production of other substances, and as a pesticide and food additive.

Acetamide

60-35-5

It is used as a solvent, solubilizer, plasticizer, and stabilizer.

Acetochlor

34256-82-1

It is used as an herbicide for weed control on agricultural crops.

Acetochlor ethanesulfonic acid (ESA)

187022-11-3

Acetochlor ESA is an acetanilide pesticide degradate. The parent, acetochlor, is used as an herbicide for weed control on agricultural crops.

Acetochlor oxanilic acid (OA)

184992-44-4

Acetochlor OA is an acetanilide pesticide degradate. The parent, acetochlor, is used as an herbicide for weed control on agricultural crops.

Acrolein

107-02-8

It is used as an aquatic herbicide, rodenticide, and industrial chemical.

Alachlor ethanesulfonic acid (ESA)

142363-53-9

Alachlor ESA is an acetanilide pesticide degradate. The parent, alachlor, is used as an herbicide for weed control on agricultural crops.

Alachlor oxanilic acid (OA)

171262-17-2

Alachlor OA is an acetanilide pesticide degradate. The parent, alachlor, is used as an herbicide for weed control on agricultural crops.

alpha-Hexachlorocyclohexane

319-84-6

It is a component of benzene hexachloride (BHC) and was formerly used as an insecticide.

Aniline

62-53-3

It is used as an industrial chemical, as a solvent, in the synthesis of explosives, rubber products, and in isocyanates.

Bensulide

741-58-2

It is used as an herbicide.

Benzyl chloride

100-44-7

It is used in the production of other substances, such as plastics, dyes, lubricants, gasoline and pharmaceuticals.

Butylated hydroxyanisole

25013-16-5

It is used as a food additive (antioxidant).

Captan

133-06-2

It is used as a fungicide.

Chlorate

14866-68-3

Chlorate compounds are used in agriculture as defoliants or desiccants and may occur in drinking water related to use of disinfectants such as chlorine dioxide.

Chloromethane (Methyl chloride)

74-87-3

It is used as a foaming agent and in the production of other substances.

Clethodim

110429-62-4

It is used as an herbicide.

Cobalt

7440-48-4

It is a naturally-occurring element and was formerly used as cobaltus chloride in medicines and as a germicide.

Cumene hydroperoxide

80-15-9

It is used as an industrial chemical and is used in the production of other substances.

Cyanotoxins (3)*

Toxins naturally produced and released by cyanobacteria ("blue-green algae"). Various studies suggest three cyanotoxins for consideration: Anatoxin-a, Microcystin-LR, and Cylindrospermopsin.

Dicrotophos

141-66-2

It is used as an insecticide.

Dimethipin

55290-64-7

It is used as an herbicide and plant growth regulator.

Dimethoate

60-51-5

It is used as an insecticide on field crops, (such as cotton), orchard crops, vegetable crops, in forestry and for residential purposes.

Disulfoton

298-04-4

It is used as an insecticide.

Diuron

330-54-1

It is used as an herbicide.

equilenin

517-09-9

It is an estrogenic hormone and is used in pharmaceuticals.

equilin

474-86-2

It is an estrogenic hormone and is used in pharmaceuticals.

Erythromycin

114-07-8

It is used in pharmaceutical formulations as an antibiotic.

Estradiol (17-beta estradiol)

50-28-2

It is an estrogenic hormone and is used in pharmaceuticals.

estriol

50-27-1

It is an estrogenic hormone and is used in veterinary pharmaceuticals.

estrone

53-16-7

It is an estrogenic hormone and is used in veterinary and human pharmaceuticals.

Ethinyl Estradiol (17-alpha ethynyl estradiol)

57-63-6

It is an estrogenic hormone and is used in veterinary and human pharmaceuticals.

Ethoprop

13194-48-4

It is used as an insecticide.

Ethylene glycol

107-21-1

It is used as an antifreeze, in textile manufacture and is a cancelled pesticide.

Ethylene oxide

75-21-8

It is used as a fungicidal and insecticidal fumigant.

Ethylene thiourea

96-45-7

It is used in the production of other substances, such as for vulcanizing polychloroprene (neoprene) and polyacrylate rubbers, and as a pesticide.

Fenamiphos

22224-92-6

It is used as an insecticide.

Formaldehyde

50-00-0

It has been used as a fungicide, may be a disinfection byproduct, and can occur naturally.

Germanium

7440-56-4

It is a naturally-occurring element and is commonly used as germanium dioxide in phosphors, transistors and diodes, and in electroplating.

Halon 1011 (bromochloromethane)

74-97-5

It is used as a fire-extinguishing fluid and to suppress explosions, as well as a solvent in the manufacturing of pesticides. May also occur as a disinfection by-product in drinking water.

HCFC-22

75-45-6

It is used as a refrigerant, as a low-temperature solvent, and in fluorocarbon resins, especially in tetrafluoroethylene polymers.

Hexane

110-54-3

It is used as a solvent and is a naturally-occurring alkane.

Hydrazine

302-01-2

It is used in the production of other substances, such as rocket propellants, and as an oxygen and chlorine scavenging compound.

Mestranol

72-33-3

It is an estrogenic hormone and is used in veterinary and human pharmaceuticals.

Methamidophos

10265-92-6

It is used as an insecticide.

Methanol

67-56-1

It is used as an industrial solvent, a gasoline additive and also as anti-freeze.

Methyl bromide (Bromomethane)

74-83-9

It has been used as a fumigant as a fungicide.

Methyl tert-butyl ether

1634-04-4

It is used as an octane booster in gasoline, in the manufacture of isobutene and as an extraction solvent.

Metolachlor

51218-45-2

It is used as an herbicide for weed control on agricultural crops.

Metolachlor ethanesulfonic acid (ESA)

171118-09-5

Metolachlor ESA is an acetanilide pesticide degradate. The parent, metolachlor, is used as an herbicide for weed control on agricultural crops.

Metolachlor oxanilic acid (OA)

152019-73-3

Metolachlor OA is an acetanilide pesticide degradate. The parent, metolachlor, is used as an herbicide for weed control on agricultural crops.

Molinate

2212-67-1

It is used as an herbicide.

Molybdenum

7439-98-7

It is a naturally-occurring element and is commonly used as molybdenum trioxide as a chemical reagent.

Nitrobenzene

98-95-3

It is used in the production of aniline, and also as a solvent in the manufacture of paints, shoe polishes, floor polishes, metal polishes, explosives, dyes, pesticides and drugs (such as acetaminophen), and in its re-distilled from (oil of mirbane) as an

Nitroglycerin

55-63-0

It is used in pharmaceuticals, in the production of explosives, and in rocket propellants.

N-Methyl-2-pyrrolidone

872-50-4

It is a solvent in the chemical industry, and is used for pesticide application and in food packaging materials.

N-nitrosodiethylamine (NDEA)

55-18-5

It is a nitrosamine used as an additive in gasoline and in lubricants, as an antioxidant, as a stabilizer in plastics, and also may be a disinfection byproduct.

N-nitrosodimethylamine (NDMA)

62-75-9

It is a nitrosamine and has been formerly used in the production of rocket fuels, is used as an industrial solvent and an anti-oxidant, and also may be a disinfection byproduct.

N-nitroso-di-n-propylamine (NDPA)

621-64-7

It is a nitrosamine and may be a disinfection byproduct.

N-Nitrosodiphenylamine

86-30-6

It is a nitrosamine chemical reagent that is used as a rubber and polymer additive and may be a disinfection byproduct.

N-nitrosopyrrolidine (NPYR)

930-55-2

It is a nitrosamine used as a research chemical and may be a disinfection byproduct.

Norethindrone (19-Norethisterone)

68-22-4

It is a progresteronic hormone used in pharmaceuticals.

n-Propylbenzene

103-65-1

It is used in the manufacture of methylstyrene, in textile dyeing, and as a printing solvent, and is a constituent of asphalt and naptha.

o-Toluidine

95-53-4

It is used in the production of other substances, such as dyes, rubber, pharmaceuticals and pesticides.

Oxirane, methyl-

75-56-9

It is an industrial chemical used in the production of other substances.

Oxydemeton-methyl

301-12-2

It is used as an insecticide.

Oxyfluorfen

42874-03-3

It is used as an herbicide.

Perchlorate

14797-73-0

It is both a naturally occurring and human-made chemical. Perchlorate is used to manufacture fireworks, explosives, flares and rocket propellant.

Perfluorooctane sulfonic acid (PFOS)

1763-23-1

PFOS was used in fire fighting foams and various surfactant uses; few of which are still ongoing because no alternatives are available.

Perfluorooctanoic acid (PFOA)

335-67-1

PFOA is used in the manufacture of fluoropolymers, substances which provide non-stick surfaces on cookware and waterproof, breathable membranes for clothing

Permethrin

52645-53-1

It is used as an insecticide.

Profenofos

41198-08-7

It is used as an insecticide and an acaricide.

Quinoline

91-22-5

It is used in the production of other substances, and as a pharmaceutical (anti-malarial) and as a flavoring agent.

RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine)

121-82-4

It is used as an explosive.

sec-Butylbenzene

135-98-8

It is used as a solvent for coating compositions, in organic synthesis, as a plasticizer and in surfactants.

Strontium

7440-24-6

It is naturally-occurring element and is used as strontium carbonate in pyrotechnics, in steel production, as a catalyst and as a lead scavenger.

Tebuconazole

107534-96-3

It is used as a fungicide.

Tebufenozide

112410-23-8

It is used as an insecticide.

Tellurium

13494-80-9

It is a naturally-occurring element and is commonly used as sodium tellurite in bacteriology and medicine.

Terbufos

13071-79-9

It is used as an insecticide.

Terbufos sulfone

56070-16-7

Terbufos sulfone is a phosphorodithioate pesticide degradate. The parent, terbufos, is used as an insecticide.

Thiodicarb

59669-26-0

It is used as an insecticide.

Thiophanate-methyl

23564-05-8

It is used as a fungicide.

Toluene diisocyanate

26471-62-5

It is used in the manufacture of plastics.

Tribufos

78-48-8

It is used as an insecticide and as a cotton defoliant.

Triethylamine

121-44-8

It is used in the production of other substances, and as a stabilizer in herbicides and pesticides, in consumer products, in food additives, in photographic chemicals and in carpet cleaners.

Triphenyltin hydroxide (TPTH)

76-87-9

It is used as a pesticide.

Urethane

51-79-6

It is used as a paint ingredient.

Vanadium

7440-62-2

It is a naturally-occurring element and is commonly used as vanadium pentoxide in the production of other substances and as a catalyst.

CCL 3 Technical Support Documents

Contaminant Information Websites

The list of websites below provides resources for general information on chemical contaminants.

Pesticide Reregistration Status
This EPA Office of Pesticide Programs provides fact sheets for pesticides in PDF form. Fact sheets include information in narrative and table form on use; health; risk (dietary, occupational, residential and ecological); and risk mitigation. Data elements include NOAEL, LOAEL, RfD, EEC, LD50, LC50 values, and critical effects for each of these. Also available are production, use and exposure assessment data.

Substance Registry System (SRS)
This EPA site provides information on substances and how they are represented in the EPA regulations and information systems. The SRS is EPA's central system for information about regulated and monitored substances. The system provides a common basis for identification of chemicals, biological organisms, and other substances listed in EPA regulations and data systems, as well as substances of interest from other sources, such as publications. You can query for substances by common identifiers, names, or alternate identifiers.

ATSDR Toxicity Profiles
This U.S. Agency for Toxic Substances and Disease Registry (ATSDR) source lists toxicological profiles in PDF form for various chemicals under "Finalized Toxicological Profiles." These profiles include health effects; chemical and physical properties; production, import/export, use and disposal information; potential for human exposure; analytical methods; and regulations and advisories for a given chemical.

USEPA Office of Science and Technology (OST): Water Science
The Office of Science and Technology (OST) is one of five water offices at EPA. It sets national environmental baselines for the quality of the Nation's waters and helps to ensure the latest water pollution science and the best available control technologies to support Office of Water program goals to keep water safe and clean. OST is responsible for developing sound, scientifically defensible standards, criteria, advisories, guidelines and limitations under the Clean Water Act and the Safe Drinking Water Act. The Office works with partners and stakeholders to develop the scientific and technological foundations to achieve clean water.